Instructions
Carry only light guns such as SMGs or pistols --- if you and your teammates pack heavier guns it will weigh you down and make you run slower.
Stay on the top balcony of the Pentagon main room. You and your teammates should keep and eye on the teleporter and wait for the Pentagon Thief to appear.
Run around in a circle on the balcony and have your teammates do the same. By the time the Pentagon Thief makes it up to the balcony he will be invisible. The red numbers represent where he is at all times --- shoot at the numbers to injure him.
Stay away from the Pentagon Thief while continuing to shoot at the numbers whenever possible. If he steals your gun, you can purchase another on the wall. Continue shooting the numbers until he has been defeated.